Perchlorate is a widespread, environmentally persistent contaminant recently discovered in U.S. groundwater and drinking water supplies. This book summarizes the most current knowledge and understandings of the extent and potential sources of perchlorate contamination, its behavior, exposure pathways in the environment, toxicology and risk assessment, and recent advances in treatment technologies for removing perchlorate. Its natural occurrence and its unique isotopic signature (between natural and anthropogenic sources) and novel detection techniques are discussed. A description of the perchlorate chemistry, microbiology, biochemistry, genetics, geochemical occurrences and environmental forensics, toxicology and risk assessment to engineering solutions and policy is provided. Also included are remediation technologies and monitoring tools for cleaning up contaminated sites including bioremediation, selective and regenerable ion-exchange, modified granular activated carbon, and catalyzed destruction.